For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningAir Hose Test
Caution: The air hose test should only be used on fully cured
urethane adhesive. Otherwise, damage to the urethane adhesive bead
could result in additional leaks.
Using a liquid detergent, diluted with water in a spray bottle, spray
the window at the edges. Begin at the bottom and grad ...
Variable Effort Steering System Description and Operation
The Variable Effort Steering (VES) system or MAGNASTEER® varies the amount of
effort required to steer the vehicle as vehicle speed
changes. At low speeds, the system provides minimal steering effort for easy
turning and parking maneuvers. Steering effort is increased
at higher speeds to provi ...
Map Data Updates
The map data in the vehicle is the most up-to-date information available when
the vehicle was produced. The map data is updated periodically, provided that the
map information has changed.
For questions about the operation of the navigation system or the update process,
contact the GM Nav Dis ...